1. Technical Field of the Invention
This invention relates to magnetic recording cartridges and transport mechanisms, and, in particular, to a cartridge and a disk drive for use in conjunction with a stretched surface magnetic recording disk.
2. Description of the Prior Art
Conventional commercially available magnetic recording tape systems have excellent fidelity characteristics, are durable and are relatively inexpensive. The main shortcoming of tape systems is that access to different portions of the tape requires a relatively large amount of time to search lengthwise of the tape.
A magnetic recording disk configuration, on the other hand, will allow random access to different portions of the recorded material since all of it is available on one plane. In addition, a plurality of magnetic transducer heads may be used in conjunction with a disk to provide rapid access to random portions of the material recorded on the disk.
Several types of recording disk configurations are either presently in use, such as the rigid and "floppy" disks used in association with computers, or proposed for such use, such as the so-called stretched surface recording (SSR) disks, one configuration of which is disclosed in U.S. Pat. No. 3,373,413 issued Mar. 12, 1968 to Treseder.
An SSR disk typically includes a concave base having a rim across which is stretched a recording medium, such as polyethylene terephthalate polymer (Mylar), coated with iron oxide. The use of an iron oxide coated polymeric material is desirable because inexpensive standard magnetic transducer heads may be used to record or read information, and stretching the polymeric material is desirable to provide an optically flat surface which may be deformed slightly to conform to the transducer head and irregularities in the surface of the head. Since the recording medium consists of a thin, taut iron oxide coated polymeric film, SSR disks are particularly vulnerable to damage from environmental contaminants, mishandling and user abuse. While much effort has been expended in the development of SSR disks, very little consideration has been given to the problems of protecting the disk and recording medium from physical damage and protecting and improving accessing to the information contained on the recording medium.
This disclosure addresses the problem of protecting magnetic recording disks in general and SSR disks in particular by providing a cartridge which encloses the disk, not only during storage, but also during operation and an SSR disk drive which accepts the cartridge and provides the mechanical apparatus necessary to access the SSR surface in the cartridge.
Ideally, a protective cartridge for a magnetic disk should provide means for locking the disk in place within the cartridge to provide protection from abuse and mishandling, isolating the disk from environmental contaminants when outside the drive mechanism, protecting the disk surface from contact by the user and protecting the recorded material itself from accidental erasure. In addition, in the drive, the cartridge must release the disk for rotation and provide access to the recording surface by a magnetic transducer head or heads. The drive mechanism must provide apparatus which acts in cooperation with the cartridge to fulfill the above requirements.